The overall goals of our investigations are to: (a) study benzo(a)pyrene (BP) metabolism by easily available human tissues and cell lines (e.g. placenta, lymphocytes, monocytes and RPMI-1788 cells) and by cytochrome P450(s) isolated from these sources; (b) prepare cDNA clones for PAH-inducible human cytochrome P450(s); (c) study the molecular biology of the human genes; and (d) employ these cDNA clones to define relationship between AHH inducibility phenotypes and susceptibility to cigarette smoke-induced lung cancer. The polycyclic aromatic hydrocarbon (PAH)-inducible cytochrome P450 mRNA(s), to be identified with specific or cross-reacting antibodies against cytochrome P450, will be isolated from placentas derived from smokers and from the lymphoblastoid cell line RPMI-1788 cells induced in vitro for benzo(a)pyrene metabolizing activity. The mRNA will be transcribed to make cDNA which will be cloned in E. coli. The positive clones will be identified by hybridization and protein translation techiques. The cDNA clones will be used to investigate the organization of the human cytochrome P450 genome; genetic regulation of transcriptional and translational products in RPMI-1788 cells; inter-individual variability in the PAH-inducible message; and in investigations designed to define relationship between AHH inducibiltiy phenotypes and susceptibility to cigarette smoke-induced lung cancer. Various methodologies intended to be used in these studies include immunological techniques involved in the raising and identification of specific antibodies, HPLC and other protein and chemical separation techniques, cell culture and recombinant DNA methodologies.